The normal way to seal a window, door or the like, is to use a seal strip which is glued, riveted or fixed by the aid of a groove to one of the surfaces being sealed.
A good seal strip must to some extent be flexible, so that it will seal the joints even when the casement and the frame move in relation to each other due to dampness or temperature changes among other things.
Due to this the best seals have been different flanged strips, tube strips, and spongy seal strips. Up to now the strips have as a rule been factory made, and then fixed to the objects in various ways. The fixing of a seal strip to the underlying surface, especially when using the tube strips, when the aim is to separate the air in the tube from the air outside, has turned out to be a difficult operation.
Even with ordinary flanged strips, there are difficulties with fastening, as right angled turns have to be made in corners, and hinges as well as locking devices have to be circumvented.
There is also a method used, in which the sealing compound is squeezed on to one surface of window and the other surface is covered with tape, and when this has been done, the window is closed, and the compound is compressed between the sealing surfaces and sets into the mold formed thereby.
The method involves a great deal of labor, because firstly one surface of the seal must be taped and secondly the superfluous compound must be cut away after setting, and the tape must be removed.
Also because the sealed joint "lives", the seal will not be tight, because it can not expand from its set form.